code: def default_resolver(
      root: Optional[PATH_TYPE], file_id: Any
  ) -> PATH_TYPE:
      file = (
          os.path.join(root, file_id) if root is not None else file_id
      )
      if os.path.isfile(file):
          return file
      raise ValueError(
          f"File ID `{file_id}` resolved to `{file}`, which does not exist. For use cases which involve first converting "
          f"the ID to a file you should pass a custom resolver when loading the data."
      )
  
file_path: lightning-flash/src/flash/core/data/utilities/data_frame.py
imports: import os
  from functools import partial
  from typing import Any, Callable, List, Optional, Union
  import pandas
  from flash.core.data.utilities.paths import PATH_TYPE
label_desc: Use image node_id 4 for calling a global function with example usage: default_resolver(root, file_id) and returns: file